JOPLIN — A 15-year-old boy accused of firing an assault rifle inside a middle school is not mentally competent to stand trial as an adult, a judge concluded in turning the teen over to mental health authorities for evaluation.

Thomas H. White was 13 when, prosecutors allege, he pointed the rifle in the direction of students and teachers, fired a round into a hallway ceiling and tried repeatedly to shoot the principal at Joplin's Memorial Middle School.

Police say the gun jammed because of an improperly seated ammunition clip, and no one was injured in the October 2006 incident. The weapon belonged to the boy's father.

White has been held in isolation at the Jasper County Jail since December 2006, facing five felony counts stemming from the school incident and an alleged attempt to escape from a juvenile detention facility. His mother has been unable to post a $250,000 bond to get him released while the criminal case is pending.

Jasper County Circuit Judge David Mouton suspended criminal proceedings in the case indefinitely and ordered White committed to the custody of the Missouri Department of Mental Health on Friday.

Mouton ordered the department to report back in six months on the state of White's mental health and whether he is likely to be able to stand trial at some point in the future.

White was evaluated at the Western Missouri Mental Health Center in Kansas City by court order in June, and a psychiatric report was delivered to the court in late July that deemed the boy mentally unfit to understand legal proceedings and to assist in his own defense.

The psychiatric report remains a closed portion of White's court file and the specifics of his evaluation have not been made public.

But a doctor and psychologist who saw him before the state's evaluation in June reported to the boy's public defenders that they believed an extended jail stay was wearing on his mental health and that he might be schizophrenic.

White stood in court Friday with his public defender, Brett Meeker, without speaking while Mouton addressed similar motions from Meeker and Assistant Prosecutor John Nicholas seeking suspension of the criminal case for the purposes of mental-health treatment.

White's supporters have sought to have the case returned to juvenile court. They contend the teen - whose father was sentenced to 18 months in federal prison after pleading guilty to being a felon in possession of a firearm - needs treatment, not jail. White's parents have previously testified that he was bullied at school and insulted because of his Mexican-American heritage.